Old gas works at Mount Stewart, Portaferry Road, Mount Stewart, Newtownards, Co. Down, BT22 2RU(?)

Ruined remains of a gas works built in the later 1850s to serve Mount Stewart House, located on the west side of Portaferry Road close to the western boundary wall of the Mount Stewart estate.

The surviving structure consists of rubble-built walls arranged in a U-shaped courtyard. The eastern wall (forming the base of the U) contains the remnants of gas extraction machinery, comprising a partly brick-faced oven-like structure with small kidney-shaped openings, presumably for coal. To the south of this stands a squat square section with battered rubble walls, from which rises a squat square battered and rendered chimney. Further south is a slightly shorter square section with a door opening on its north face. The flat roof of this southern section now serves as a platform with commanding views over Strangford Lough, accessed via a modern wooden open staircase positioned against the high plain south wall. The north wall is lower and partly demolished.

Historical records indicate that the 4th Marquess, in a letter dated July 1854 to his step-mother Frances Vane-Tempest, described plans to improve Mount Stewart, including "a Gasometer built by Sanderson for about £250 but fittings etc. by Cubitt". The works appear on the revised Ordnance Survey map of circa 1860 and likely date to the later 1850s. Estate ledger entries from 1859 record "sundry items for gas works and gas meters", with further references to the complex until 1914. The house itself was subsequently converted to electricity. The Ordnance Survey map of circa 1860 indicates a small building formerly standing just west of the east wall, no trace of which now remains.